Torque expression and bracket deformation of the Orthos and Orthos Ti orthodontic bracket

Deformation of the orthodontic bracket upon wire engagement may result in torque dissipation within the bracket rather than transmission to the tooth and its supporting structures. The purpose of this study was: (1) to quantify the amount of torque expression and (2) to quantify any deformation as a result of such increasing torque expression.;A sample of 30 Orthos and 30 Orthos Ti brackets were tested with custom software using a novel application of digital image correlation.;Orthos Ti brackets produce significantly greater amounts of torque from 48° to 24° returning to a neutral position. Titanium brackets exhibit greater variance in torque expression but less variance in deformation. Orthos stainless steel brackets exhibit significantly greater amounts of bracket slot deformation in comparison to the Orthos Ti.;Digital image correlation is an accurate means of analyzing an orthodontic bracket's structural response to an applied moment of force created through archwire rotation in vitro.